Changes in ultraviolet radiation in the 1990s: Spectral measurements from Reading, England

摘要

Spectral, ultraviolet irradiance measurements have been made since 1990 at Reading (England). Ancillary measurements using a photodiode show that UV measurements are frequently affected by clouds. Consequently, it is not practical to simply use irradiance measurements to study possible ozone-related changes in UV-B over the timescale of the measurements. However, taking ratios of irradiances in bands covering UV-B and UV-A wavelengths can be used to reduce the cloud influence on measurements. Using these ratios and ozone vertical column measurements, the anticorrelation between ozone and UV-B irradiances measured at the ground is demonstrated. These data also show that between 1993 and 1997, UV-B at Reading has increased by 4.3%, compared to a decrease in ozone of 5.9%. The UV-B increase is not a statistically significant trend, however, and serves only as an indication of the changes observed. [References: 14]